Rev matching, down shifting and heal toe, MANUAL TRANS ONLY

Love rev matching, but heel and toe on the street is too much for me and my passenger. I need to really depress the brake in order to have enough room to swing my heel around, and I would need to be going track speeds to do that, which inevitably makes driving super harsh. I heel and toe all the time on my racing sim, but those pedals are at the same height and closely spaced. So, I don't think it is a matter of not knowing how to do it, just the rate at with I am driving. Perhaps a spacer or different pedal plate could help. The PP brakes are just too strong to be able to feather and then blip with the heel.

Norm Peterson said:

Holding the engine revs up with the clutch fully disengaged can let the input shaft and countershaft slow down well below where the synchros want them to be, where they'll make the synchros have to speed them up (and work a little harder in the process) to get the shaft speeds matched. This can even happen on an upshift if the weather is cold enough and the gear lube stiff enough, and you don't run 1st gear out quite far enough because its oil is cold and a little stiff.

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This won't happen unless you press in the clutch and stay too long in neutral then your input shaft would slow down. As long as you are in gear, your input shaft is locked in gear spinning.
In fact most up shifts, the syncros are used to slow down the input shaft.
If you really want to save the syncro, you have to double clutch up and down shifts.

Norm Peterson said:

A fully synchronized transmission only accomplishes synchronization for the gear being shifted into. Constant mesh (what I think TexReb is thinking of) is something entirely different.

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Not all constant mesh transmissions have synchronizers, and not all synchronized transmissions are fully synchronized. Synchromesh is a term used to denote a synchronized constant mesh gearset.

Double clutching is necessary for any non-synchronized gear (constant mesh or sliding). I don't know of any sliding gears that were ever synchronized.

jasonstang said:

I guess they could if they added a cone clutch on the sliding gear to engage before the gear slides in?

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maybe a spring wheel on the sliding gear that rolls against the teeth of the fixed gear before engagement... I think the need for synchronization is part of what spurred the development of constant mesh gear sets. Sliding gear sets only really have a weight advantage, as the sliding gear can mesh with multiple fixed gears.

Another thing I forgot to mention is that the transmission output assembly is essentially your whole vehicle connected to the transmission by the tires. Your vehicle is, as far as the transmission knows, just a huge energy storage device... E = 1/2mv^2
1/2 * 4000 lb * 66 ft/s = 132000 ft lb / s @ 45 mph. ... or 240 Horsepower @ 45mph.

TexasRebel said:

floating gears is granny shifting

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:shrug: Granny shifting to me has always been the exceedingly sloooowwww, draggggged-outtt kind of shifting that would guarantee you'd lose every drag race. All the motions were there, but you could almost time them with a sundial.


To 'float gears' in a "situation", you do have to either keep rolling or have a good battery, a healthy starter, and possibly a modified clutch pedal interlock switch if the clutch release mechanism isn't completely MIA. Been there.


Norm

I've heel and toe shifted since 1967 when I learned to drive and got a licence. I still do, there's isn't a drive in my Mustang goes by without doing it. I learned to do it driving my old man's 1961 Austin Healey 3000, that was a challenge as synchros were not the best in those days. Back then you had to do it or you'd destroy the gearbox. Unless you just wanted to look and sound like a dork dumping the clutch instead of downshifting correctly with a nice blip.

The name is a misnomer, I don't use the heel, I roll the side of my foot on the gas pedal, I don't have the extended pedal just the factory Ford one and it works fine. I road raced in the 80s and 90s and everyone did it if they wanted to be remotely competitive. It was just a given that you did it. Formula cars with non-synchro gearboxes demanded it. You are kidding yourself if you think you can race competitively without heel/toeing with a pure OEM manual.

The S550 Mustang PP has overboosted brakes and it makes it more difficult than it should be to be smooth on the street, my '11 S197 with the 4 pot ones was not quite so grabby on light braking. When using the brakes hard though it all works very nicely.

Norm Peterson said:

Holding the engine revs up with the clutch fully disengaged can let the input shaft and countershaft slow down well below where the synchros want them to be, where they'll make the synchros have to speed them up (and work a little harder in the process) to get the shaft speeds matched. This can even happen on an upshift if the weather is cold enough and the gear lube stiff enough, and you don't run 1st gear out quite far enough because its oil is cold and a little stiff.

A fully synchronized transmission only accomplishes synchronization for the gear being shifted into. Constant mesh (what I think TexReb is thinking of) is something entirely different.



Don't you lift off the throttle for easy/normal upshifts? Same thing, really, that while you're moving the shift lever you're letting the input side revs decay to match what the new gear wants. Only for a downshift the revs are too low to begin with so you have to kick them "upstairs" first so they can fall back.


Norm

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I get it...but on your last sentence, why do I need to cause the revs to fall back before I release the clutch pedal? Wouldn't it synchronize better if I just let the revs be at the desired RPM.

When I downshift, 1)I do release the throttle (as on easy upshifts), then 2)I press the thottle in again until I get to the desired RPM, and then 3)I release the clutch with the lower gear. Seems to work perfectly...why would I add a step 2.5)release the throttle and let the revs fall?

This is the part that confuses the hell out of me of blipping vs rev matching, never found the need to blip (press and release throttle, then release clutch), I just rev-match (press the throttle to rev up and release clutch).

Sally15 said:

I double clutch and rev match, always. When you get that down, the ride as as smooth as an automatic. You can select non-sequential gears as well.

This car is not factory set for heel/toe, not for me anyway. At 6', I'm leary of the DIY pedal modification.

Never had any clutch issues. I do this because it makes me feel engaged with the car. Couldn't not do it really. My first cars, second gen supras, were friendly to heel/toe. The last one had 145k on factory clutch and still going. Don't abuse the car and no difference imo.

Also, my PP was extremely clunky brand new. Only 7k now but a much smoother.

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I always double clutch and rev match on downshifts, in DD. I even do double clutch when I heel-toe, just for the fun of it. I know some will say that this is not necessary, but I just enjoying the fun of it, plus the benefit of super smooth shifts.

zxd9 said:

I've tried heel-toe a few times but the PP brakes are so touchy I end up braking way too hard when I blip the throttle. May not be as much of an issue on the track because you probably do brake pretty hard all the time.

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ForTehNguyen said:

need to do the spacer mod for the gas pedal, it makes the gas pedal more flush with the brake pedal during braking. It helps immensely. And very cheap modification.

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zillah said:

Love rev matching, but heel and toe on the street is too much for me and my passenger. I need to really depress the brake in order to have enough room to swing my heel around, and I would need to be going track speeds to do that, which inevitably makes driving super harsh. I heel and toe all the time on my racing sim, but those pedals are at the same height and closely spaced. So, I don't think it is a matter of not knowing how to do it, just the rate at with I am driving. Perhaps a spacer or different pedal plate could help. The PP brakes are just too strong to be able to feather and then blip with the heel.

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This. My brakes grab so hard and fast, even when pressed lightly, that it makes it very uncomfortable to even try heel toeing. Also, I'm 6'4 which seems to be a problem. I have spacers and the steeda extended gas pedal, and my foot would still have to be able to break to try and blip with my heel or toe. I'll try rolling it sideways and see if that works.

Generally though, I blip to rev match on downshifts. After replacing my resonator with an h-pipe it made it much easier to hear and feel the right RPMs. I'm installing Pype Bomb axle backs this week, so that should help

* Flamesuit on* If I wanted a boring ass DD... I buy an F-ing camry... If i'm going to throw 35k+ on a s ports car.... I'm going to treat it as such and Rev match every opportunity I get.

Rev-match almost every down shift on the street. Can't really heel-and-toe unless I'm at the track and can really press hard on the brakes to form a good base for rotating my heel over to the gas pedal. My feet aren't wide enough to do the roll method on the Mustang, although it works very well on the GTI which does allow me to heel/toe that car on the street.

-T

Rebellion said:

I get it...but on your last sentence, why do I need to cause the revs to fall back before I release the clutch pedal? Wouldn't it synchronize better if I just let the revs be at the desired RPM.

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Because it's easier to kick the revs a bit high and from there just let them come down on their own like you do on a normal upshift, than it is to hold them at any fixed rpm. It's also more conducive to keeping your right foot ready for braking if it's not busy holding the engine to some rpm.


Norm

Everyone, I would like to say Im happy to see this thread growing! I have read some very good things already and it seems that others have as well. When I get some extra time this week, I plan to edit the OP and update it with basic info such as the difference between rev match, double clutch ect.

Keep the info flowing everyone!

I rev match every time there is a downshift. It just feels right mechanically to get everything close to the same RPM before engaging gears. Shifting in general and rev matching is second nature now after a decade plus of only manual cars.

One of my first cars, a CRX, had the clutch go out on a drive home from work. I had to drive about ten miles home with no clutch. A few weeks prior, some of my buddies and I were joking around trying to shift without using the clutch. We figured it out, but it was pretty hard to feel "no load" on the engine so the shift lever would pop out (and back in) easily. Stop lights were a suggestion that day, I would just roll slow enough to wait for the green.

I haven't tried to no clutch shift the mustang yet and man I hope I don't need to!

jasonstang said:

Then you've never driven your car hard on a track.
No heel and toe under heavy braking before a turn is a recipe for loosing control.

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Oh so true. I did it wrong last summer and almost lost it at high speed.